Preparation and electrochemical characterization of (100 - X)(0.7Li2S·0.3P2S5)·xLiBr glass-ceramic electrolytes

Abstract

Glass and glass-ceramic electrolytes of (100 - x)(0.7Li2S·0.3P2S5)·xLiBr (x = 0, 5, 10, 12.5, 15 and 20) (mol %) were synthesized by mechanical milling and subsequent heat treatment. Glass powders with no crystal phase were obtained by mechanical milling. The conductivities of the glasses increased concomitantly with increasing LiBr content. The conductivity at x = 20 was 3.1 × 10-4 S cm-1 at room temperature. The Li7P3S11 crystal with high Li ion conductivity was precipitated in the glass-ceramics obtained by heat treatment. LiBr crystal was also precipitated in the glass-ceramics containing LiBr as a starting material. The glass-ceramic at x = 10 showed conductivity of 6.4 × 10-3 S cm-1. It increased to 8.4 × 10-3 S cm-1 by control of the milling period to prepare the precursor glass. 90(0.7Li2S·0.3P2S5)·10LiBr glass-ceramic with high Li ion conductivity had a wide electrochemical window of 10 V. An all-solid-state lithium secondary battery using 90(0.7Li2S·0.3P2S5)·10LiBr glass-ceramic as an electrolyte was charged and discharged successfully.